Ultrasound Shear Wave Speed of the Transverse Carpal Ligament During Pinching

The thumb and transverse carpal ligament (TCL) have an anatomical connection and biomechanical interaction. Understanding the in vivo mechanics of this interaction is valuable for the study of hand and wrist biomechanics. The objective of this study was to quantify this biomechanical interaction using shear wave elastography. The hands and forearms of healthy volunteers (n = 11) were submerged in water. A pinch meter was placed between the thumb and index finger. An ultrasound transducer was placed at the distal carpal tunnel to image the cross section. Ultrasound and shear wave elastography images were taken for pinch forces of 0, 10, 20, and 30 N. The shear wave speed (SWS) was measured on the TCL. Repeated measures ANOVAs were used for comparisons (α = 0.05). SWS increased with increasing pinch force (p = 0.007). The SWS changed by 0.27 m/s [95% CI: (−0.01 m/s, 0.55 m/s); p = 0.0572], 0.54 m/s [95% CI: (0.07 m/s, 1.01 m/s); p = 0.0294] and 0.83 m/s [95% CI: (0.27 m/s, 1.39 m/s); p = 0.0079] when the pinch force was increased from 0 to 10 N, 0 to 20 N and 0 to 30 N. TCL SWS increases with in vivo loading.